1. Field of the Invention
The present invention generally relates to an automatic feedback adjustment device for a digital antenna, and in particular to the adjustment of receiving direction and elevation angle for a digital antenna unit that is based on closed-loop feedback of actual direction of the digital antenna to automatically perform adjustment to the optimum receiving direction.
2. The Related Arts
Digital television (DTV) and digital audio broadcasting (DAB) have founded the new era for multimedia home entertainment. In particular, the digital television and the digital audio broadcasting have become available to homes, allowing human to receive information from a wide range of channels. However, the conventional DTV and DAB systems both need a digital antenna unit to receive signals, such as a plate shaped satellite antenna of DVB-S (Digital Video Broadcasting-Satellite) and receiving antennas of DVB-T (Digital Video Broadcasting-Terrestic) and ATSC (Advanced Television Systems Committee). All of these have to be adjusted manually to the best/optimum receiving direction, and through the observation of the receiving signal quality through the naked human eye, to manually adjust the digital antenna unit to its best direction and elevation angle.
However, the conventional digital antenna unit adjusted manually to the optimum receiving elevation angle and direction costs more time and labor, and the adjustment of the optimum direction may change from time to time because of the orbital positions of artificial satellites, the climate, the global tides, the magnetic fields, the sun spot and other affecting factors. And this makes it necessary to adjust the digital antenna unit to the optimum receiving direction manually over and over again, making the adjustment of the digital antenna unit extremely hard and inconvenient.
Further, considering of attaching an electric motor unit to the digital antenna unit used to adjust the direction and elevation angle of the digital antenna unit, although using the electric motor to drives the adjustment of the direction and elevation angle for the digital antenna unit can improve over the manual adjustments, but it cannot adjust the optimum receiving position of digital antenna unit quickly and accurately.
In the previous references, for example Taiwan Utility Model No. M285858 discloses a rotation adjustment device of satellite antenna, and Taiwan Patent No. I246793 discloses an angle adjustment device and a satellite antenna having the angle adjustment device, both presenting conventional manually adjusted satellite antenna device. These conventional devices need to be manually adjusted to the optimum receiving direction.
In addition, Taiwan Patent No. M264673 discloses a transmission device that performs automatic adjustment based on signals received from a satellite. However, the reference did not mention the method for adjusting to the optimum receiving position, and instead, it still needs to be adjusted to the optimum receiving position by human hands.
Taiwan Patent No. I251374 discloses a system and a method that automatically adjust an antenna to a position corresponding to the highest intensity of signal. However, the system and the method requires a transmitting signal to be transmitted to an antenna device first and the antenna device then creates a main wave beam, constantly changing phase of the transmitting signal to change the direction of the main wave beam and scan the main wave beam through all directions to identify the direction of a wireless-signal user end, and adjusting the strongest part of the main wave beam to point to user position, allowing the user to receive better receiving quality. This system and method takes more time to search and scan, and the user end antenna is in fixed condition, rather than being automatically adjustable. Whether the user end antenna can really receive the strongest receiving signal is not promised, and meanwhile, this system and method is limited to a wireless area network system in a specific space, not suited for the adjustment of the typically known digital video/broadcasting receiving antenna.